System traffic

[tewhill]

I'd like to know if any of the Refs out there have come up with a quick and
easy way of determining haw many ships are in a system/port at a given
time. My goal is to have a snappy answer when my PC's enter a system and
the sensors sweep the system. I assume that any answer has to be tied into
the various trade ratings. But before I go through the trouble of
inventing a method of my own, has anyone tackled this qustion?

 

[robject]

Sure. I use a sloppy-but-it-works method:

(1) Locate the "best" local trading partner for that world. For instance, the "best" trade partner for Rhylanor is probably Porozlo.

(2) Tally up points for each one, using some sort of consistent scoring method:
+1 point for A/B starport, -1 point for E/X starport.
+1 point for High pop, -1 point for Low pop.
+1 point for TL A+, -1 point for TL 5-.
+1 point for Rich, -1 point for poor.
+1 point for In or Ag, -1 point for Ni or Na.

(3) For a super-quick-and-dirty method, take the average of the two numbers, subtract one, round up. Or down. Call that number "x".

(4) The number of ships insystem at any one time is 10^x. Ten to the xth power. 1d10 with x zeroes after it. In fact, I'd say a 1 with x zeroes after it, just to be quick about it.

(4a) I'd say that 75% of those ships are of types A, A2, M, and R. The rest are Scouts, Patrol, and various small cruisers and whatnot: nearly all ships are less than or equal to 1000 tons.

(4a) I'd also say there are also [x-1] Very Large (10,000 tons+) ships in-system. If the system has a naval base, I'd say there's a 50-50 chance that that "Very Large ship" is in fact an Imperial Cruiser squadron or similar. Otherwise I'd say it's a megacorporate freighter, with escort of course.


EXAMPLE: "You're in Porozlo, and you see..."
Rhylanor (4 points), Porozlo (3 points).
Average = 3.5
Minus one = 2.5
Round up = 3

Number of ships = 10^3
around 1000 ships:

750 Merchants (type A (150), A2 (200), M (200), and R (200))
250 Others (type S (50), C (50), T (50), K (50), Y (50), whatever)
2 Very Large ships:
one Imperial Cruiser squadron (d6 x 10k tons)
one Megacorp freighter (d6 x 10k tons)
with a group of Gazelle escorts

NOTE: You don't have to have exactly 1000 ships in the above example: if you spill over even by a factor of two or three you're still fine.


ANOTHER EXAMPLE: "You're in Tureded, and you see..."
Tureded (1 point), Macene (1 point)
Average: 1 point
Minus one: 0 points

Number of ships: less than ten. I'll say 5, and make up the types, sticking close to my 75-25 ratio of merchants to others.

3 merchants (A2, A2, M)
2 others (Y, C)

NOTE:

If the exponent is ZERO, then there's between 0 and 9 other ships in-system. If the exponent is less than zero, then there's a 10% chance (or less) that there's any ships out there at all. You get the idea.


...and that's how I'd do it.

 

[RainOfSteel]

You don't have to invent your own, GT:Far Trader has the method. Implementing it might be a bit difficult (involving either spreadsheets or databases, and lots of calculations).

However, someone has done this (to some extent), and you can check trade levels at: Map of Traveller Charted Space.


EDIT------------
Ok, I just did some further checking, and it appears to only has high level trade level info. Sorry.

 

[Jame]

There's a chart at the back for GT:BTC that has a list for this: first determine the starport, then roll for how many ships there are, and then what type, and then where they are, whether they're leaving or coming and what they're doing on the way. It requires some time, but it can be useful.

 

[robject]

As Chris and Jame have noted, Traveller has come up with formulae for dealing with this. From what I hear, GT:Far Trader is an excellent reference. I think I remember its author talking about the formulae he was going to use. He's a bona-fide economist, isn't he?

I say, make it simple for you, and have the results appear reasonable to you. The Traveller Universe usually only deals with one significant digit. Get a ballpark estimate and y'all can get down to serious play.

After all, all you want to know is really an idea of "how busy IS that port, anyway?" So whatever works for you. My sloppy way can be made even sloppier by only looking at the starport, TL, and Hi/Lo pop codes. Merely glancing at the UWPs can then give you an indication.

 

[RainOfSteel]

GT:Far Trader was by Chris Thrash, Jim MacLean, and Steve Daniels.

I used to see Mr. Thrash's posts here on CotI (but not lately).

 

[tewhill]

BtC does have tables for generating individual starship encounters. And Far Trader has some very elegant ways to characterize system economies as a whole. But I don't see that either of them has addressed my question specifically in the form a detailed procedure. If I've missed something, please point me to the page.
I like robject's method very much and intend to use it. I would also suggest added some addtional mods to the list:

+1 for worlds on the Spinward Main
-1 for worlds requiring J2
-2 for worlds requiring J3

Thanks for all your replies.

 

[RainOfSteel]

Originally posted by tewhill:
BtC does have tables for generating individual starship encounters. And Far Trader has some very elegant ways to characterize system economies as a whole. But I don't see that either of them has addressed my question specifically in the form a detailed procedure. If I've missed something, please point me to the page.
I like robject's method very much and intend to use it. I would also suggest added some addtional mods to the list:

+1 for worlds on the Spinward Main
-1 for worlds requiring J2
-2 for worlds requiring J3

Thanks for all your replies.

Well, I believe you can calculate the amount of tonnage shipped in offworld trade via GT:Far Trader. With that, you divide by 52 to determine the weekly tonnage available.

I've seen the numbers, I've got a Spinward Marches spreadsheet that includes these numbers, but blast if I can remember where I got it.

Here's an excerpt:
</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">World Tons/Week
---------- -----------
Zeycude 7,933
Reno 103,846
Errere 21,202
Cantrel 1
Gyomar 96,154
Thengo 115
Rio 1,923
Gesentown 23,077
Cronor 11,033,654</pre>[/QUOTE]Oh . . . I belive that's developed via GT:Credits, which don't resemble CT:Credits, unfortunately.


EDIT----------
I notice that Entrope's Pop Multiplier of 7 is retained in this data, it shows that world shipping 161 million dTons/week.

 

[tewhill]

So, what steps would you then take to translate the tonnage per week into a number of ships in port/system at the PC's point of arrival?

 

[RainOfSteel]

I'd take a look at the ships I planned to have as standard freighters in my campaign. Small, medium, large, etc.

I'd check their cargo capacities.

Then I'd look at how I conceptualized trade.

Trade in the 3I IMTU is based heavily on mid-range cargo and passenger ships in the 20-40K dTon range, operated by large shipping concerns. Large bulk freighters are operated by subsidy in order to carry bulk foods and liquids (hydrocarbons, or water to Hydro 0 worlds) to worlds that need them (usually TL-11 or less IMTU).

A J-2/M-1 20K dTon freighter, I think we can say, could transport at least 5K dTons of cargo.

Regina (the TL-12 version) ships 2,153,846 dTons/week.

If I estimate that, say, 70% of trade is carried by this type of freighter, and then posit average cargo capacities for other types of freighters, we come up with:

</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">Share % Share Amnt Cargo Cap. Ships/Week
70% 1507692.308 5000 301.5384615
15% 323076.9231 50000 6.461538462
10% 215384.6154 250 861.5384615
5% 107692.3077 50 2153.846154
Total Ships/Week: 3323.384615</pre>[/QUOTE]Wow! Regina turns out to be a busy port!


Or, in other words, I fake it!

 

[robject]

tewhill,

My actual article on quick-and-dirty traffic guesstimations is at:

http://eaglestone.pocketempires.com/RJStarportNew.html

There are related articles there, too, such as figuring out how big your starport should be and what kind of system defense might be there.

http://eaglestone.pocketempires.com/

 

[tewhill]

Outstanding, rob and rain.
This is just the kinda stuff I was looking for.
Thanks again.

 

[RainOfSteel]

Originally posted by tewhill:
Outstanding, rob and rain.
This is just the kinda stuff I was looking for.
Thanks again.

Anytime.

 

[Hal]

When I was faced with the same question you allude to, I used the spreedsheet/database on the spinward marches - figured out which planets would have trade with the planet in question, and then determined what the yearly trade by volume was between the trade partner and the planet in question. Then I determined what the weekly trade was and used the rules for determining how much trade between the world was established merchant trading (liners) versus how much was assigned to tramp freighter business. I used the arbitrary limitation that liners were ships of 800 dtons or larger, while tramp freighters were ships of between 100 dtons to 600 dtons, with the bulk around 200 dton ships.

Example I used for Ianic and surrounding trade partners...
</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;"> DIST Tonnage Max
Hex World Allegiance Parsec yr/wk Ships
1824 Adabicci Imperial 1 35,752/688 11
2124 Lunion Imperial 2 49,646/955 22
2327 Strouden Imperial 5 27,693/533 12
3124 Mora Imperial 12 7,399/142 3
2728 Duale Imperial 8 4,545/87 2
2036 Glisten Imperial 15 4,596/88 3
1223 Gram Sword World 7 4,127/79 2
2521 Heroni Imperial 6 2,251/43 1
2620 Natoko Imperial 7 3,205/62 1
2228 Persephone Imperial 6 3,244/62 1
2715 Porozlo Imperial 13 1,160/22 .5
2716 Rhylanor Imperial 12 1,475/28 .5
1325 Sacnoth Border World 6 5,137/99 2
2125 Shirene Imperial 2 2,543/49 1
1825 Zaibon Imperial 2 2,924/56 2
2024 Derchon Imperial 1 1,947/37 .5 </pre>[/QUOTE]Max Ships represents the maximum number of 200 dton free traders based on the cargo capacity of same for GURPS TRAVELLER. As you can see from the listing I produced, Ianic would receive some 65 200 dton free trader ships per week. In instances where the trade might have been a few 400 dton ships, they likely arrived from Lunion or Adabicci, as those two planets have the largest amount of trade involved. But it doesn't rule out 600 dton ships from those two ports, nor does it rule out Strouden or Glisten as ports that might have sent a larger free trader.

As you can see, this is not something you can determine just at a moment's notice, and requires some GM work in advance. But then again, if you do this for all the ports within a subsector in advance, you should be able to prepare something you can rest easy about. As pointed out by the others, you can always just create a random encounter type of thing and wing it.

 

[Hal]

Oh, I should point out, all that data on Ianic assumed only free trader trade - as the BTN was not high enough to result in Regular Liner trade routes.

Also note, that according to some, this data makes no sense because Ianic, a Low tech desert world shouldn't be seeing this level of traffic. Unfortunately, based SOLELY upon the rules of FAR TRADER rather than the "houserules", such a scenario is in fact, plausible based on population rating.

As ever, your milage may vary.

 

[Antony]

I tried this with Stave when I world grabbed it which BtC said was noted for its exports of "Stave Corn" of course since the world seemed to be able to only fill a single bulk carrier per year how notable could it be.

 

[Antony]

I tried this with Stave when I world grabbed it which BtC said was noted for its exports of "Stave Corn" of course since the world seemed to be able to only fill a single bulk carrier per year how notable could it be.

 

[robject]

Originally posted by Hal:
Example I used for Ianic and surrounding trade partners...
...As you can see from the listing I produced, Ianic would receive some 65 200 dton free trader ships per week. ...

My goal was to cook up a way to get close-enough to spreadsheet numbers without doing much work.

So using my quick-and-dirty system, Ianic scores a -1, and Lunion scores a 5. They average out to 2. So that points to around 10^2 ships at any one time:

75 traders or so
25 miscellaneous or so
maybe 1 very large ship

Since Ianic is a "Rich" world, many of those 25 ships are probably Yachts, Safari ships, and escorts.

 

[kaladorn]

The spreadsheet BTN method suggested is interesting, but only accounts for merchant traffic, and that says nothing about relative proportions of military or non-military, non-trade traffic. Both of these may be influenced by the amount of trade traffic (military tends to protect trade) but aren't directly correlated.

As an aside, Stave Corn may be remarkable for being unique rather than plentiful.

 

[Hal]

Originally posted by robject:
</font><blockquote>quote:</font><hr />Originally posted by Hal:
Example I used for Ianic and surrounding trade partners...
...As you can see from the listing I produced, Ianic would receive some 65 200 dton free trader ships per week. ...

My goal was to cook up a way to get close-enough to spreadsheet numbers without doing much work.

So using my quick-and-dirty system, Ianic scores a -1, and Lunion scores a 5. They average out to 2. So that points to around 10^2 ships at any one time:

75 traders or so
25 miscellaneous or so
maybe 1 very large ship

Since Ianic is a "Rich" world, many of those 25 ships are probably Yachts, Safari ships, and escorts. </font>[/QUOTE]I took a look at your system and I agree that it is quick and dirty when it comes to giving numbers. The issue regarding how many ships arrive in Ianic arose due to the potential Piracy game I was working on. There, I needed to know how many ships arrive and with what freqency. I did leave out the scout ships that would have been in system, and I did leave out escort ships - as that was a variable not handled by any of the Traveller systems (ie for every X tons of ships, there are Y tons of escorts). When I determined what Ianic's trade value should have been, I noted that it was 3 for the population rating, +.5 for its tech level, -.5 for its starport for a total of 3 for WTN. Since the WTN can not be higher than the lowest by 5, the Highest BTN is 8. Reading the information on Feeder routes, some of the tonnage will be shipped by liners and some by freight tramps. BTN's of less than 8 are all serviced by tramp freighters only - and all tonnage is done by tramp freighters. At BTN's of 8, only 10 to 50 dtons of cargo are available per day, just enough to fill the hold of a 200 dton ship if I recall correctly once per two days (on average).

What does this mean for any type of traffic? With the scout base there, plus the merchant traffic (a quantifiable value in a rough estimate), and perhaps some escorts - the actual ships present both inbound and outbound is going to be some 130 ships overall. On a day to day basis, this number would be lower. If using only averages, then there should be no more than around 20 ships in/outbound per day. This is roughly 25% of the figure given with your rough and ready numbers.

Keep in mind two things. One, GURPS FAR TRADER may be off in its estimations and Two, I may be off on my estimations.

The real irony is that if you use the values given in LBB versus what others claim is common sense - Ianic wouldn't even be getting the traffic that I calculated based solely upon GURPS FAR TRADER values. Clearly, which game system you use also indicates what the traffic patterns will be based on the economics rules in use.